3 1604 016 762 033
First Annual Shenandoah Research Symposium
National Park Service
U. S. Department of the Interior
Digitized by the Internet Archive
in 2012 with funding from
LYRASIS Members and Sloan Foundation
First Annual Shenandoah Research Symposium
National Park Service
143 South Third Street
Philadelphia, PA 19106
Natural Resources Reports Number 11
This volume includes papers presented at the First Annual
Shenandoah Research Symposium held at Shenandoah National
Park, April 9-10, 1976. The papers cover such topics as
plant sucession on abandoned homesites; vegetation responses
to management burning at Big Meadows, Shenandoah National
Park; a spring burn's impact upon vertebrates at Big Meadows;
a consideration of black bear populations in Virginia; and
the Shenandoah salamander.
Some of the papers report on research projects conducted
in cooperation with Shenandoah National Park but at no
park expense. The National Park Service strongly endorses
such mutually beneficial research whereby the Service
acquires professional studies about its parks, and researchers
are afforded opportunities to utilize park resources .
Superintendent Robert R. Jacobsen initiated the symposium
because of his enthusiasm for cooperative research at
Shenandoah National Park. He intends to continue welcoming
such scholarly study there and values the associations it
produces with colleges and universities. He would be
delighted to respond to inquiries about possible future
research, which should be addressed to:
Superintendent Robert R. Jacobsen
Shenandoah National Park
Luray, Virginia 22835
We wholeheartedly support Mr. Jacobsen' s interest in
cooperative research and believe that his symposium
was one of the Region's outstanding activities in 1976.
Benjamin J. Zerbey
Acting Regional Director
Vegetation Responses to Controlled Burning
at Big Meadows, Shenandoah National Park 1
W. Dean Cocking, Assistant Professor of
Biology, Madison College
Effects of a Spring Burn Upon the Vertebrate
Community at Big Meadows, Shenandoah National Park. . 4
Peter Dalby, Assistant Professor of Biology,
University of Virginia
Plant Succession on Old Homesites 12
Elwood Fisher, Associate Professor of Biology,
The Endemic Salamander, Plethodon shenandoah ,
of Shenandoah National Park 15
Richard Highton, Professor of Zoology,
University of Maryland
History of Botanical Research in Shenandoah
National Park 18
Peter M. Mazzeo, U.S. National Arboretum
Study of Black Bear Populations in Virginia 28
Jack W. Raybourne , Game Research Biologist,
Virginia Commission of Game and Inland
Status of Knowledge of the Geology of Shenandoah
National Park 38
John C. Reed, Jr., Chief, Office of
Environmental Geology, U.S. Geological Survey
Monitoring Forest Insect Outbreaks in the Shenandoah. .47
Timothy C. Tigner, Entomologist, Insect and
Disease Investigation, Virginia Division of
VEGETATION RESPONSES TO CONTROLLED
BURNING AT BIG MEADOWS
W. Dean Cocking"
The fire ecology project at Big Meadows in the central
section of Shenandoah National Park is a cooperative effort
involving local park service personnel, scientists from
several educational institutions and Dr. Robert Stottlemyer
from the Mid-Atlantic Regional Office of the National Park
Service. The experimental prescribed burns carried out in
the Spring of 1975 for the purposes of our study were the
result of efforts by Ray Schaffner, Robert Jacobsen,
Clark Baker, and many others. This paper will describe
some of the preliminary results of our participation in
the project. The majority of the field work was carried
out by Steve Lilly and Emily Baxter, graduate students
in the Department of Biology at Madison College. We have
been looking at the growth rates and community composition
of the regenerating meadow vegetation and hope that the
resultant data, combined with the soil and faunal observa-
tions of Dr. Norman Chris tensen and Dr. Peter Dalby, will
give a complete picture of the ecosystem response to pre-
scribed burning .
Big Meadows is at an intermediate stage of secondary succes-
sion and is therefore similar to the majority of the
communities within Shenandoah National Park. The progress
of succession at this site, however, has been periodically
set back by fall mowing, the frequency of which has increased
during the last decade until it is now virtually an annual
occurrence. The purpose of this management practice has
been to maintain open space adjacent to the Byrd Visitor
Center and has resulted in a mosaic of herbaceous "grass-
land" and shrub "briar" communities . The increasing size
of black locust stems over the last decade has made the
mowing practice more difficult, and this project is designed
-Assistant Professor of Biology, Madison College,
to look at the feasibility of using fire to maintain the
earlier stages of succession. Without some form of manage-
ment, the meadowland will disappear and young successional
forest will take its place.
The present mowing technique has two major disadvantages.
First, it is an increasingly expensive and time consuming
endeavor. Second, it appears to be stabilizing the community
as a shrubland of Rub us spp . (blackberries and dewberries)
and Robinia (black locust) . Should this happen, the herbacious
species will disappear from the region due to their inability
to compete successfully. Information from this study will be
helpful in making management decisions concerning whether
mowing, burning or a combination of both will be appropriate
in the future .
Sixteen small plots (approximately % acre each) were
selected within the dry, upland part of Big Meadows. One
half were in the "grassland" community type and the rest
in the "shrub-briar" community. Within each community type
two plots were mowed as usual in the fall of 1974, two
were burned on April 15, 1975, two received both treatments,
and two received neither treatment and served as experimental
Detailed discussion of the data from this study will be
presented later, along with the results of a much more
extensive spring burning carried out last week. However,
it is possible to discuss some of our observations at this
time. One of the primary investigations concerned the immediate
effects of the burn on the physical environment. Temperatures
during the burn were approximately 300 to 350 °C, a rela-
tively warm fire, but not extremely hot in comparison
with temperatures attained in some forest fires. We examined
soil temperatures five days after the burn and found slight
increases in the blackened areas as a result of the
greater absorption of light by the dark soil surface.
The impact of this warmth on spring growth remains to be
established. Dr. Christianson has analyzed soil samples
taken two months following the burn and reports increases
in potassium, calcium, magnesium, nitrogen and other ions.
This greater nutrient mobility may promote better growth
during the subsequent summer, however, this also remains to
be determined. Another question which interested us was
the rate of recovery from burn to green meadowland. Regrowth
was extremely rapid in all burned plots, and very little
evidence of the fire remained by mid-summer.
Quantitative assessment of the burn impact was carried
out in two ways. We sampled the tissue by physically
collecting the above ground vegetation, drying it in an
oven, and determining the dry weight of living and dead
components of various species groups . We also used a
sampling frame to determine the amount of soil surface area
covered by the individual species . Recovery in "grassland"
at the end of the growing season in August was more complete
than that of the "shrubland." However, both community types
were very repairable following the prescribed burns .
We are also interested in changes in species composition
of the communities which might result from the use of
burning as a management practice. Initial examination of the
data indicates that some species, e.g., the Fragaria , Solidago ,
Achillea , Potentilla and Rubus, increase in relative
cover while others, such as Dennstaedtia , Polytrichum ,
Lycopodium and Robinia , decrease following the burn
treatment. The dynamics of these species composition changes
will hopefully become more evident following the present
In conclusion, we feel assured from the initial project that
burning and mowing are similar in their effect on the com-
munity and that the use of fire to set back succession will
not result in prolonged damage to the ecosystem. We are not
presently in a position to predict the effect on individual
species. However, we do know that species present in the
meadow are dependent on the open conditions of herbaceous
and shrub communities and will certainly disappear if the
community completes the successional process and returns to
EFFECTS OF A SPRING BURN UPON
THE VERTEBRATE COMMUNITY AT BIG MEADOWS,
SHENANDOAH NATIONAL PARK
Peter L. Dalby*
I hope to make this presentation a bit broader in coverage
and possibly a bit more philosophical in nature than just
examining the effects of a spring burn upon the vertebrate
community at Big Meadows. Since plants and animals are
difficult to separate completely from each other because of
their interrelationships, you will note some overlap with
the report given by the plant ecologist on this project,
Before progressing further, I would like to acknowledge the
support of the National Park Service, Tall Timbers Research,
Inc., an organization dedicated to fire ecology research,
and of course, the Shenandoah Natural History Association.
A past V.P.I. & S.U. graduate student, John Niess, also
contributed to the earlier portions of this study. The
field work was completed while the author was associated
with V.P.I. & S.U.
Superficially, and from a non-ecologist ' s viewpoint, one
might accept the argument that the use of fire is warranted
simply to determine if it is an effective and economical
tool for maintaining cleared areas. Overlooks, old home-
stead sites, and others such as Big Meadows fall into this
category. Does mowing, brushing, or bush-hogging such sites
create more, the same, or less damage than a controlled
burn? Which technique, the time-honored method or burning,
is most successful in reducing unwanted species for the
longest period of time? Above all, what is the cost-benefit
ratio built into the time-honored methods versus controlled
^Assistant Professor of Biology, University of Virginia,
As interesting as the above questions are, studying the
effects of controlled burning in Big Meadows has progressed
further than simply attempting to reduce the ubiquitous
black locusts ( Robinia pseudoacacia ) and briars (blackberries,
Rubus sp.). An attempt is being made to monitor the kind
and the intensity of change due to fire, both to the plant
and the animal community. In other words, more than a
casual examination is being given to the locusts and briars,
two of the major early succession woody plants invading Big
Meadows and other open areas in the park. Less dominant
and less conspicuous species are also being qualitatively
and quantitatively sampled. It is important to document not
only how the fire directly affects the animal life, but also
how the change in vegetation affects the local fauna.
There is an amazing dearth of information concerning the
effect of fire upon the flora and fauna of the eastern
United States. This is in sharp contrast to the respectable
data bank accumulated for the western and also for the
southeastern United States. Most of this information was
gathered by those interested in forest management or forest
recovery; much less is known of the effects of fire upon
grasslands, particularly as it pertains to the eastern
United States .
There are several reasons why Big Meadows was chosen for
the burn project over other areas within Shenandoah National
Park. First, Big Meadows is the largest (125-150 acres)
high altitude (3500 ft. or 1067 m.) grassland meadow in the
park. Therefore, it allows a great deal of flexibility
concerning experimental design, especially as it pertains
to plot size and number. Second, it is logistically ideal
because it is reasonably centralized in respect to the
institutions involved in the study and it is near a road
and housing/ camping facilities. Third, the importance of
Big Meadows, both in the past and the present, serves as an
additional rationale for efforts to preserve its exceptional
qualities without further delay.
There is some evidence that the Indians maintained the field
condition of the Big Meadows area through the use of fire.
Strawberries, blackberries, and blueberries were abundant
during various portions of the summer; probably other
"crops" were gathered also. In addition, the meadow
certainly attracted bison, elk, white-tailed deer, several
species of rabbits and hares, woodcock, and probably other
Presently, Big Meadows is a focal point in the park's
camping and naturalist programs. Birding, watching for
deer and other mammals , identifying flowers , and general
hiking activities are only a few features which make Big
Meadows so popular. As the forest tends increasingly to
dominate the park scene, clearings such as Big Meadows
present an alternate vista of openness to the park visitor.
More importantly, Big Meadows and other open areas in the
park serve as a refuge for a number of plant and animal
species partially or solely dependent upon a grassland
community for their existence.
Because of the plot sizes agreed upon by all those involved
in the project (see Dr. Cocking' s presentation for a
description of the plots) , it was decided for at least the
first year to concentrate mainly on sampling the invertebrate
soil and litter fauna. This is for very obvious reasons.
They are plentiful, and there are good sampling techniques
so statistical analysis of the data is reasonably easy. We
hope to examine the small mammal (rodents and shrews) and
bird communities, however, the plots are rather small for
this kind of work. Although the data that can be gathered
may be meager, it still provides a ballpark estimate of what
happens as a result of controlled burining.
The collection of invertebrates was done during ten sampling
periods, at three week intervals, starting in April and
finishing at the end of October. By using a stratified
random design, four soil and litter samples were taken from
each 25 m. square plot. The sampling was taken with a 10%
inch (25 cm.) diameter metal band, about 5 inches (12% cm.)
in width. With the band encircling the sampling area, a
shovel cut the sod along the inner perimeter of the band.
Then the 1-2 inches (2.5-5.0 cm.) thick plug of sod was
pried loose, placed into a plastic refuse bag, and sealed.
At the university, usually half of the samples were placed
in a cooler (5°C) and the remainder processed immediately.
A Berlese funnel system was constructed in order to extract
the invertebrates. A cloth cover over the funnel prevented
escape from the top. A lamp over each funnel provided
enough heat to drive the invertebrates out of the soil and
into a jar (containing a solution of 907 o ethyl alcohol)
attached to the funnel. After a week the sod was discarded
and the jars containing the results were capped and stored
until the material could be identified. The remainder of
the samples which had been under refrigeration were then
placed on the funnels. Approximately 500 samples were
collected and processed.
The small mammal community in the study plots was monitored
by using an approximately equal number of small (54 x 64 x
171 mm.) and large (75 x 75 x 227 mm.) Sherman live traps.
Nine traps were placed in each 25 m. square plot, following
a grid pattern in which the traps were set at about 8 m.
intervals. Rolled oats was used as bait, and the traps were
set at dusk and checked the following morning. This procedure
was followed for two consecutive nights. Trapping occurred
at the beginning of the study, just prior to burning, again
during the middle of the summer, and lastly in October at the
termination of the study. A total of 648 trap-nights (one
trap set for one night equals one trap-night) were accumulated.
The birds were periodically watched during the season,
particularly by Mr. Niess, who was employed as a summer
naturalist at the Big Meadows Visitor's Center. Most of the
observations were taken during the beginning of the study when
home territories and feeding areas became established. The
results of this portion of the study are of a qualitative
nature. When the opportunity arose, observations on other
animal species were also taken.
The Burlese funnel invertebrate material remains to be
identified and I have no preconceptions about changes that
might have occurred during the study. However, we were able
to make some observations. Of considerable importance to
the pollinating insects was their use of the unburned and
unmowed briar patches as a food base during the spring blos-
soming period. One of the interesting facts concerning
briars is that they are biennial plants, and, once mowed or
burned back to ground level, any recovery during that growing
season is entirely vegetative. Flowering occurs only on
second year and older cane. With the annual mowing and bush-
hogging which has occurred for the last 30 or so years on Big
Meadows , pollinating insects have certainly had one food
resource literally cut out from under them. Annual use of
fire will have the same effect. Although the smaller blue-
berry bushes could escape the mowing operation, the others
were trimmed to the point where they too did not flower to
any appreciable degree until the second year. Fire had the
same effect; in fact fire might be a bit more severe in the
sense that fewer stems escape damage. As a result, the
pollinating insects had two plant types eliminated from their
food resources. Certainly later in the year these same plants,
if allowed to flower, would have provided a substantial amount
of fruit for many fruit-eating species of insects, birds,
and mammals .
As for small mammals, essentially nothing was found. In the
spring one adult short-tailed shrew ( Blarina brevicauda ) , was
found dead during an invertebrate sampling period. It may
have been killed by a fox and discarded because of their
apparent ill taste. One subadult meadow vole ( Microtus
pennsylvanicus ) was captured during the last trapping period
of the season. Such a paucity of small mammal life in Big
Meadows has existed for quite some time as evidenced by
trapping records for the last 5-10 years on file at park
headquarters. I would speculate that part of the reason
might be due to the large biomass of nonvascular plants
(mainly mosses) found on the study sites. Over the years,
mowing has probably favored that type of growth over the
grasses and sedges. I suspect that by the proper use of fire,
one can increase the amount of sedge and grass cover. In fact,
Dr. Cocking 's report tends to verify this. With a larger
biomass of sedges and grasses there might be an increase in
the number of meadow voles . This in turn could tend to
increase the number of owls , hawks , skunks , and foxes , all of
which prey to some extent on this species. In other parts of
Big Meadows, for instance, in some of the lower and higher
areas away from the study sites, there are limited patches of
dense grass cover inhabited by meadow voles, as discerned by
observation of their runways. These mice can serve as nuclei
for future invasion into other parts of Big Meadows.
There are only about a half dozen woodchuck ( Marmota monax )
holes near or within the study sites, but one quickly notices
that these are almost exclusively found in the briar thickets ,
although the animals ' feeding usually takes them out of this
cover. If an attempt is made to eliminate all the briars
from Big Meadows, it is certain to have a dire effect upon
the woodchuck population. From much walking in Big Meadows
I would estimate that there are 50-100 active woodchuck dens,
nearly all associated with the briar and to a lesser degree
the locust (1-3 m. in height) stands. The preference of some
low woody growth around potential den sites is well documented
for woodchucks and its elimination or reduction will decrease
the woodchuck population. This might not be entirely
undesirable except it must also be kept in mind that rabbits,
skunks, and other species, including some amphibians and
reptiles, also utilize the same holes.
The information on birds is mostly qualitative in nature.
There are several generalizations which can be made, however,
concerning the effects of the burn upon them.
1. Fire does not seem to have an immediate negative
effect on birds. In fact, several species which
appear to prefer feeding areas with short cover,
such as robins ( Turdus migrator ius ) , vesper
sparrows ( Poocetes gramineus ) , grackles ( Quiscal us
quiscula ) , and starlings ( Sturnus vulgaris ) seemed
to be more frequent in burned than in unburned
areas. This activity continued until the new
growth was well established by mid-summer. The
loss of leaf litter and possibly the warming of
the soil made the bird prey more visible and
probably more active because of the warmer soil
temperatures. It is obviously difficult to
determine whether a bird has a behavioral prefer-
ence for a particular habitat or is at a site
because of food availability.
2. Vesper sparrows, song sparrows ( Melospiza melodia) ,
field sparrows ( Spizella pusilla j^ indigo buntings
( Passerina cyanea ) , bluebirds ( Sialia sialis ) and
possibly a few others selected the burned, but
still standing dead cane of the briars, and the
standing, but dead locusts, as perching sites. This
observation was not discernible until several weeks
into the study when unburned briar and locust sites
were well leafed. It seemed to hold true under
several different circumstances: a bird would
alight to "rest," to sing a territorial song, or
to perch between periods of foraging activity on
the ground. Obviously such perching sites gave
the bird a clear field of vision.
3. Two known species, namely the song sparrow and the
towhee ( Pipilo erythrophtohalmus ) nested in the
standing unburned, unmowed , 1-3 m. tall locusts.
While both species are common in the area, mowing
or burning every 2-3 years instead of every year
would insure added nesting sites for these two
species, among others.
4. Burning or mowing is necessary to maintain an
open courtship area for woodcock ( Philohela minor ) .
Very preliminary results suggest that courting males
in burned sites remain in such sites. During a
good spring evening there is no doubt, after
listening to the large number of woodcock
utilizing Big Meadows, that it is an important
Data on a number, probably a majority, of the species men-
tioned above are less than conclusive. However, the picture
described, albeit crudely drawn, can still be recognized as
a picture. Certainly the finer lines have to be added.
Other characters , such as skunks , opposums , and deer are
still missing from the drawing. The herps (reptiles and
amphibians) pose a special problem. There is a small
population of wood frogs (Rana sylvatica ) , spring peepers
( Hyla crucif er ) , and American toads ( Bufo americanus ) that
breeds in the several small ponds situated in Big Meadows.
The ponds often dry up before the tadpoles undergo meta-
morphosis so it is a marginal breeding site at best. Yet
the number of other potential breeding sites in the immediate
vicinity is unknown. Probably burning will not harm their
breeding activities, but still they should be monitored.
The reptiles are represented by box turtles ( Terrepene
Carolina ) , green snakes ( Opheodrys vernalis ) , ring-necked
snakes ( Diadophis punctatus ) , and garter snakes ( Thamnophis
sirtalis ) . The green snakes and garter snakes are typical
field snakes and, as a result, are rather unique to Big
Meadows. The effect of burning on their welfare is unknown.
In fact, at this point there are more "unknowns" than
"knowns" concerning all the above species and the effect of
fire on their existence. Yet, based on what is known a
few concluding remarks can be made.
Big Meadows owes much of its uniqueness to its great
diversity of plants; the diversity of animals found at Big
Meadows is partly dependent on this plant diversity. The
complex, mosaic distribution of plants and animals within
the meadow allows for the following:
1. Certain animal species are dependent upon
essentially a single plant species habitat. For
example, if you have a pure species stand of
briars , then very likely there are going to be a
certain invertebrate and vertebrate species that
will, for all practical purposes, lead their
entire life (or life cycle) within that briar
2. Many species are ecotonal in nature. That is,
some species may nest in one habitat yet move to
another to forage. These species are dependent
upon two or more habitat types in close proximity
for their livelihood.
3. As open meadows continue to shrink every year in
the park because of forest encroachment, there
eventually comes a time when there is not enough
room in the meadow to sustain viable populations
of either of the above two types. In effect,
animals inhabiting the area are now woodland
forms, the meadow forms having been extirpated.
It is the complexity, the mosaic pattern of life in Big
Meadows which aids in making the area the plant and wildlife
showplace that it is. There is a need to keep the complexity
in order to maintain the richness, yet at the same time
there must be a pureness in order to insure the survival of
other species which contribute to the area's richness. Is
mowing or fire the best management technique to use in order
to sustain or even increase Big Meadows' richness? Which-
ever method is eventually utilized, burning or mowing in
swaths is highly recommended, following a 2-3 year
rotational program. This by itself will be an improvement
over the practice of mowing the whole field every year.
Burning or mowing should be done as early (burning) or as
late (mowing) as possible in order to minimize damage to
the animal (and plant) community. Burning or mowing should
be thought of as successful management tools only if they
can control in a more or less steady-state condition the
complex of plant and animal life presently found on Big
Meadows. In other words, the spread of briars and locusts
is to be controlled; there is no desire nor ecologically
sound rationale to eliminate either from Big Meadows .
Finally, fire has been documented to play a very important
natural role in some ecosystems. It may be that fire once
played an important ecological role in this part of the
country also. Fire has always been a double-edged sword
for man. It is up to us at Shenandoah National Park to learn
how best to use the tool that Mother Nature has been using
for eons .
PLANT SUCCESSION ON FORMER HOMESITES
The need for this study occurred to me while I was directing
a Master of Science thesis for Paul R. Lee, a Shenandoah
National Park naturalist, on "A Study of the Impact of the
Exotics Lonicera japonica and Alanthus altissima on the
Shenandoah National Park Ecosystem." I felt that results from
such an investigation would be currently useful to the interpre-
tive staff of the park, as well as to academicians of the
The park is really a very unique laboratory for ecologists.
It is an experimental plot of immense proportions where
cultivation and other forms of land use had completely changed
the natural environment in almost every section. This region,
occupied by some 350 families, was almost instantly allowed
to start its return to primeval conditions , providing
scientists with a rare opportunity to study roles and patterns
of plant succession in this ecosystem.
For the sake of clarity many plant ecologists draw rather
fixed, over-simplified models of plant succession. Due to
the number of variable habitats and factors of an area as
large as the park, these models do not hold true when investi-
gated under actual field conditions. In fact, succession
is a mosaic of a variety of sere-types, often in areas of close
proximity. The soil type, degree of mineral exhaustion, amount
of erosion, exposure to sun and wind, slope, type of natural
cover, local animals, fires, "mother seed trees,'' frost
pockets, elevation, and related factors are foremost in deter-
mining the rates and patterns of succession.
Peter M. Mazzeo (1966) catalogued the species of exotics
at the Skyland site. His study and the one by Paul Lee (1973)
are the only published attempts at accessing the succession
in any part of the park prior to my studies of former
^Associate Professor of Biology, Madison College, Harrisonburg,
homesites. Basically I am trying to record the exotics
that have survived, and to determine the degree of their
adaptability in the midst of encroachment by the endemics.
I am also trying to interpret the order and rate at which
the endemics advanced into the homesite and surrounding
fields. I am using increment borings to determine the age
of the dominant trees on the site, when in question or if
relevant. 1 make a plant list for each site, noting the
incidence of dominant, co-dominant, common, and sparse species,
both exotic and endemic.
For the most part, the techniques I have employed are the
observational methods of a naturalist. I grew up in a similar
environment during the depression years and can interpret
and relate to the mountain farm and life-style. I used the
1927 through 1937 series of United States Geological Survey
fifteen minute quadrangles in locating the sites. Though
many of the old trails are no longer visible I can generally
take a compass sighting from the spring to the homesite
and find the house foundation readily. All homesites had a
nearby spring, a prerequisite to life in the mountains.
I intend to visit each site during two seasons, spring and
autumn. In the spring I look for flowering bulbs and other
spring flowering plants. Late summer and autumn data catalogues
plants not seen in the vernal season. At this time I have data
for at least one of the two seasons for ninety percent of
the sites in the Southern Section of the park. I have some
data for the sites in the Central Section, but very little
for those in the Northern Section.
The Lonicera j aponica (Japanese vine honeysuckle) is always
present on homesites at lower elevations. The Alanthus
altissima (tree of heaven) , Vinca minor (common periwinkle
or graveyard myrtle) , Syringa vulgaris (common lilac) , and
Hemerocallis fulva (day lily or beauty of the day) are the
four exotic species of ornamentals most frequently found
at all elevations, The various species of Rosa are also
numerous , but it is very difficult to differentiate
between the many varieties and species . Of the exotic
herbs, the Taraxacum officinale (common dandelion) and Arctium
minus and A~ lappa (common and great burdock) appear to
be most common.
Of the endemic plants , it appears that Pinus virginiana
(Virginia pine) , Prunus serotina (black cherry) , Sassafras
species, Robinia pseudo-acacia (black locust), and Crataegus
species (hawthorn) are the most agressive pioneer species of
the formerly cultivated areas in the park. The soil qualities
such as dryness and fertility, among other factors, determine
which of these species dominates the earliest sere. On a
few sites I have found species other than the above which
first colonized the vacated land, but rarely is this the case.
In addition to cataloguing the exotic and endemic plants
I have kept a sharp eye for artifacts on or near each site.
These items, along with the size and workmanship of the
foundation of the former house, gives me some idea of the
life-style and occupation of the former residents. I also
record bird species and other animals seen at each site. Since
the type of sere is still changing, this information may
be useful to later investigators.
Hopefully I shall complete the study of the Southern Section
of the park and have a manuscript prepared by 1978.
THE ENDEMIC SALAMANDER, PLETHODON SHENANDOAH,
OF SHENANDOAH NATIONAL PARK
Mr. Raybourne's paper on the black bear reviews the interest-
ing work being done on the largest vertebrate in Shenandoah
National Park. I want to talk about some of the research we
have been doing on the two smallest terrestrial vertebrate
animals living in the park.
The first is the Shenandoah Salamander, Plethodon s henandoah
Adults of this species are only three to four inches long.
As far as we know, this salamander is found nowhere else
in the world, although it has close relatives in the Cheat
Mountains of West Virginia and in the Peaks of Otter area of
the Blue Ridge of Virginia. Not only is the Shenandoah Sala-
mander restricted to the park, but it is apparently confined
to northwest facing talus slopes of only three of the park's
highest mountains, Hawksbill, Stony Man, and the Pinnacle.
On all three of these mountains the entire distribution of
the Shenandoah Salamander is in each case no more than three-
quarters of a mile in diameter.
The Shenandoah Salamander occurs in two color phases , or
morphs , which are merely genetic color pattern variations
of a single species: the unstriped or dark color morph
and the striped color morph characterized by a narrow red,
reddish yellow, or yellow dorsal stripe. The two morphs
occur in approximately equal frequencies on Hawksbill
Mountain, but the striped morph is much more abundant than
the unstriped morph on Stony Man Mountain, and we have found
only the striped morph on The Pinnacle.
The red-backed salamander, Plethodon cinereus , is probably
the commonest terrestrial vertebrate over much of its range
in northeastern United States and southeastern Canada. It
*Prof essor of Zoology, University of Maryland, College
is a close relative of the Shenandoah Salamander and is very-
similar in appearance, occuring in both striped and un-
striped color phases , but is usually somewhat smaller and
more slender than shenandoah . Striped cinereu s have a wider
dorsal stripe than striped shenandoah , and the stripe is
more often red than yellow. The body of Shenandoah National
cinereus is slightly more elongated than that of shenandoah
with an average of twenty trunk vertebrae as opposed to
nineteen in shenandoah . There is more dorsal brassy-colored
flecking on the back of unstriped cinereus than on unstriped
shenandoah , and the belly of shenandoah is much darker than
that of c inereus because the white mottling is greatly
Although the red-backed salamander occurs in virtually all
the wooded areas, it apparently is usually absent from the
dry open talus slope areas where there is little soil and
evaporation rates are extremely high. This includes the
major part of the talus slopes on Hawksbill and Stony Man
Mountains, but suprisingly we have found cinereus throughout
most of the talus slope on The Pinnacle Mountain where
conditions are perhaps different from those in most of the
park' s slopes .
Most of our field work in the park was done in 1965 and 1966
soon after we discovered shenandoah . It was officially
described and given a scientific name in 1967. During that
period two graduate students, Richard D. Worthington and
Robert G. Jaeger, and 1 did extensive field work on the
distribution of the two species in the park. We failed to
find shenandoah on any of the other high nearby mountains ,
even those with northwest facing rocky talus slopes.
The closest relatives of shenandoa h are nettingi , which
inhabits the spruce forests in the Cheat Mountains of West
Virginia, and hubricht i , an inhabitant of the high deciduous
forests of the Peaks oF Otter region of Virginia. The distri-
bution of the three forms is one we regard as relictual; the
three presently isolated populations are now very restricted
in their distributions but at one time probably had a much
more widely distributed common ancestor. At first we thought
that shenandoah might have subsequently become adapted
to living only in rocky talus habitats , but the brilliant
work of Robert G. Jaeger on the ecology of shenandoah and
cinereus has clarified the reasons for their present ecologi-
cal distributions, at least on Hawksbill Mountain. I am sorry
he was not able to attend this meeting to tell you about his
In a series of experiments on the moisture requirements of
shenandoah and cinereus , Dr. Jaeger found that both species
have similar moisture and substrate preferences: both prefer
soil to rock under dry conditions but do not differ in the
substrate preference in wet conditions. Probably partly
because of its larger size, s henandoah is better able to
withstand desiccation than cinereus . Thus shenandoah is not
confined to the talus slopes because it is adapted only to
this habitat; indeed it would probably do better in surrounding
woodlands now occupied by cinereus . It is surviving only in
a suboptimal habitat that is periodically too dry for cinereus
to live in.
Dr. Jaeger did additional experiments in enclosures set up
in the field in both talus and woodland habitats. Ten individ-
uals of cinereus were placed in cages in the talus and in
the soil outside the talus. All of the cinereus in the soil
survived for 12 weeks , but none in the cage in the dry talus
survived that long. A similar comparison of shenandoah
resulted in moderate survival in the dry talus and complete
survival in the soil habitat. When 10 individuals of both
species were placed in a single cage, one in each habitat,
shenandoah had a higher rate of survival in the talus , but
cinereus had a much higher rate of survival in the soil out-
side the talus. Since shenandoah did very well in the soil
without the presence of cinereus , Dr. Jaeger concluded that
cinereus was competitively superior to shenandoah in the
soil outside the talus. There is considerable evidence to
indicate that food may be the limiting resource for which
the two species are competing. Immediately after a rain, these
salamanders emerge from their burrows and find food in the
form of small insects and other forest floor inhabiting in-
vertebrates to be very abundant. Because of their susepti-
bility to desiccation, these animals are not able to come out
to feed on dry nights , so food may be regularly in short
supply. It is interesting that the largest shenandoah , being
so much bigger than adult cinereus , are able to survive in
the woods outside the talus by eating larger food items than
cinereus can consume, but presumably their young are not
able to compete successfully with cinereus and are never
found more than a few feet from the talus habitat.
It would appear, then, that shenandoah is a formerly wide-
spread species that has been displaced by a more modern and
efficient competitor. It survives only in a suboptimal
habitat that is periodically too dry for cinereus because
of its better ability to withstand desiccation. But the future
is probably bleak for shenandoah because as the talus errodes
more and more soil is produced and cinereus is at present
entering into these pockets of moist soil and will presumably
displace shenandoah and eventually cause its extinction.
HISTORY OF BOTANICAL RESEARCH IN
SHENANDOAH NATIONAL PARK
Peter M. Mazzeo*
It is always a pleasure to return home, as it were, to
Shenandoah National Park. I had the distinct pleasure of
working here for three seasons, while a student in college
and shortly thereafter. So it's nice to be home again and
especially here at Skyland, the heart of Shenandoah National
When I first came to the park area in 1962, I was interested
in the vegetation of the area. No one before that time had
done a serious study, except for the various checklists and
supplements that had been prepared. So I began a rather
intensive study of the vascular vegetation in the park, and
tried to supplement what was already known. My remarks are
based primarily on a history of the botanical collecting
undertaken before that time and an up-date based on subse-
Although Shenandoah National Park will be only forty years
old on July third, the eve of our nation's Bicentennial, most
of the botanical study that has been done in this area dates
back to around the turn of the twentieth century. Very little
is known about the botany of the area before that time. There
is one indication going back to the very early 1800 's which
is somewhat interesting and perhaps explains in part
the reason for the apparent lack of interest in the botany
of these mountainous areas, namely, lack of accessibility
to the park area. Benjamin Smith Barton, a Philadelphia
physician and botanist, and a good friend of Thomas Jefferson,
was making a survey trip down through the Great Valley of
Virginia and parts of West Virginia. In his journal dated
August 26, 1802, Mr. Barton wrote the following: "Between four
and five o'clock in the afternoon, I left Hays and passed
*U.S. National Arboretum
through the gap in the mountains called Rock Fish Gap. I
observed nothing very remarkable on the way. On the mountain,
I observed some of the same kind of red earth so common
in the area in which I had just left, [referring to the
Triassic soils of the piedmont plateau area] . Near the
summit of the mountain, there is a tavern. But I thought it
proper to proceed on my journey. I readily discerned that
the descent on the western or rather nothwestern side of the
mountain is much less considerable than the ascent on the
east or southeast side [of the mountain]." As time went on,
roads were built through the area, but, for whatever reason,
botanical studies were not made until the present century.
The first apparent collections of any consequence date to
1901, and were made by Edward S. Steele and his wife, who were
visitors to Stony Man Camp here at Skyland. The early Stony
Man Camp was one of the main drawing cards to the Blue Ridge
Mountains, one of the first beloved areas, as it were. It
is interesting to note that of all the taxonomy collected,
that is, all the various species that were collected and
documented with herbarium specimens by Steele in 1901 from
the vicinity of Stony Man Mountain, all but one have been
relocated today in basically the same area. A notable
exception is the bearberry, Arctostaphylauva-ursi , which is
not only rare in this part of the country but has not been
seen, to the best of my knowledge, since 1901 when it
was collected at an altitude of 3600 feet on Stony Man
Mountain. I know that Mr. Stevens has been looking for it,
and hopefully this plant may be rediscovered in the park.
Two other botanists, William Palmer and W.H. King, both of
the Smithsonian Institution in Washington, made collections
in the period of 1901, 2, 3, 4, 5, and thereabouts. The next
major collections that we encounter in the park were made
by Iver Tidestrom, a botanist with the U.S.D.A. in Washington.
Many of his collections date back to 1912, 1913-14, again
primarily in the vicinity of Stony Man Mountain.
In the nineteen twenties Edgar T. Wherry, at that time a
geologist with U.S.D.A., made extensive collections in the
Blue Ridge Mountains. Dr. Wherry is probably more familiar
to many of us for his work with phlox. He is the author of
a monograph on the genus Phlox that today is the standard
reference work for that plant group. Most of his collections
are located in herbaria either in Washington or Philadelphia,
where he later became a professor at the University of
Pennsylvania. Dr. Wherry was also very helpful to me when I
was preparing my book on the ferns of Shenandoah National Park
P.L. Ricker, the president of the Wildf lower Preservation
Society in Washington, made extensive collections in the
Blue Ridge Mountains in the '20s and for many years there-
after. He was very instrumental in locating some of the
rather unusual plants found growing in the vicinity. There
are other botanists from the Washington area, others from
Baltimore and Philadelphia, who made collections to document
the flora of the park at that time.
The main intensive collecting period began in the 1930' s,
primarily in conjunction with the establishment of the National
Park in this part of the eastern United States. We find many
notable botanists collecting at that time, including F. Raymond
Fosberg and Egbert H. Walker, both botanists in the Washington
area. They made intensive field studies, documented the flora
with herbarium specimens, and catalogued over eight hundred
species which they published in the first major listing of
vascular flora of the park area, entitled the "Preliminary
Check List of Plants of the Shenandoah National Park," in
1941. The very first publication dealing with the flora of
the park, however, was published in 1935. This was not about
the vascular plants but rather the fungi found growing in the
area. It was published by John Stevenson, a curator in the
National Fungus Collections of the U.S.D.A. in Beltsville,
During this period, W.H. Camp of the New York Botanical Garden,
who was especially interested in the Ericaceae , the Heath
family, made numerous collections in the area. He identified
many hybrid forms growing in the park. As many of you probably
know, it is not always easy to identify distinct species
of the park's blueberries because of the hybrid forms found
E.H. Fulling, also of the New York Botanical Garden, did
extensive collecting in the area during the mid-1930's. In
1936, he published a paper on a new variety of Balsam fir
named Abies intermedia , the Blue Ridge Fir. It is rather
unusual to find this particular variety so far south in the
Blue Ridge Mountains , or the Southern Appalachian Mountains ,
but here it is on Stony Man Mountain, the Crescent Rocks
area, and Hawksbill. A few years earlier, M.L. Fernald of
Harvard University had described a very similar plant from
New England, and later Abies intermedia was reclassified
and grouped in with Abies balsamea variety phanerolepsis .
Dr. Ruskin Freer, a professor of botany at Lynchburg College,
made extensive collections in the area of southern Shenandoah
National Park between Rockfish Gap and the Roanoke area. On
various occasions he would come up and meet with botanists
collecting in what is now the park. His work has been instru-
mental in furnishing a history of botanical collections and
research in the park.
Arther H. Leeds and Frances Harper, both of Philadelphia,
also made many collections important to the documentation of
the park's flora. J.E. Benedict, Jr., a seed tester from the
Washington area, made valuable collections. I understand
his private herbarium was recently acquired by V.P.I, and
S.U. at Blacksburg.
All of the various plant species that had been collected and
documented with herbarium specimens to prove the existence
of these various taxa from the park area, were catalogued
and published in 1941 in the "Preliminary Check List of
Plants" by Fosberg and Walker.
The National Park was established and dedicated in 1936:
the Skyline Drive and Appalachian Trail system were constructed,
providing access to the "backbone" of the Blue Ridge Mountains.
Accordingly, many more botanists became interested in the
During the early 1940 's an Englishman by the name of E.K.
Balls, who was in the Washington area with the War Department,
made extensive collections, primarily on Old Rag Mountain.
This was the first major botanical "expedition" to the Old
Rag area. Mr. Balls produced several new records for the
H.A. Allard, another U.S.D.A. botanist from Washington, was
interested in the flora of the northern part of Virginia
and made extensive studies in the Bull Run Mountain area,
as well as the Blue Ridge and various other places in
northern Virginia and northern West Virginia. O.M. Freeman
of the U.S.D.A. also collected quite a bit in the Blue Ridge
Mountains. Dr. F. Ewan of Tulane University made various
collections near the Washington area. E. Graff, Assistant
Secretary of the Smithsonian Institution, collected in
the park. Fred J. Hermann, perhaps the most knowledgeable
botanist on the genus Carex , the sedges, made and identified
numerous collections. E.P. Killip of the Smithsonian Institu-
tion and Warren H. Wagner, Jr. , at that time a graduate
student, but now a professor at the University of Michigan,
collected in the Blue Ridge Mountains. (Dr. Wagner is
most notably known for his work on the ferns .) Frances W.
Hunnewell of Wellesley, Massachusetts, also made many collec-
tions in the Blue Ridge Mountains , including some in
Shenandoah National Park.
There is a very good story to mention at this time. If you
browse through Gray's Manual of Botany , you will see listed
in there Diervilla sessilifolia , which is a species commonly
found in the southern Appalachian Mountains. When Mr.
Hunnewell made a collection from Warren County, Virginia,
along the Skyline Drive, it was cited in the eighth edition
of Gray's Manual of Botany as being a rather disjunct
population. Fortunately , he had made a herbarium specimen.
Some botanist later questioned the validity of that disjunct
record from Warren County, and when the specimen was scruti-
nized by other botanists it was decided that the plant was
not really Diervilla sessilifolia , but rather Diervilla
lomicera , a species that is common in the Shenandoah National
Park and other mountain regions of eastern North America.
This is a good illustration of the importance of specimens
for documentation of botanical research.
Fosberg and Walker published the first supplement to their
"Preliminary Check List" in 1943. Meantime, members of the
park staff began studying the area's vegetation: W.D. Chick,
a park naturalist, a park forester named Moore, and Griffing,
the landscape architect. Unfortunately many of their plant
catalogs were not documented with herbarium specimens but
only were named in the park Check List. Now we are not sure
if some of those taxa are correctly represented in the park
or not. In 1948 Fosberg and Walker published a second
supplement to the Check List.
One notable plant that had been discovered in the southern
section of the park was Xerophyllum asphodeloides , the turkey
beard, a member of the Lily family. It s a rather unusual
plant, common in the New Jersey Pine Barrens, found here on
some of the mountains in the southern section of the park.
It is rather curious that this plant should be in that area.
I've been there to look for it myself a couple of times and
have never yet seen it in flower. I've seen the plant growing
there with a persisting inflorescence, the flower cluster and
stalk from a previous year. The plant apparently blossoms
every other year, so hopefully I'll get a chance to see
it in flower and will collect it when I do.
In 1945, the first major paper and Check List on the Bryophytes
of the park was published by Irma Schnooberger and Frances
E. Wayne, both from the University of Michigan. This is
the only such paper on this section of the plant kingdom.
Botanists continued to collect in the area during the 1950 's,
and, in 1955, a third supplement to Fosberg and Walker's
"Check List" appeared. In 1959, Fosberg published a fourth
paper entitled "Notes on the Park Flora."
The first major publication involving a group of vascular
flowering plants in the park was published in 1958 by Grant
and Winona Sharpe entitled 101 Wildflowers of Shenandoah
National Park , a very handy small guide book to the more
common wildflowers in the area. Unfortunately this book is
now out of print. This book was one in a series the authors
have prepared for various national parks such as Shenandoah,
Mt . Ranier, and other national parks in the western part of
the country. The Sharpes are associated with the University
of Washington in Seattle.
During the 1960's, more and more people became interested in
the flora of the park and we find for the first time a
major interest developing among amateur botanists. Many
people, with permission, collected specimens or took photo-
graphs that provided or documented park records . These include
Virginia Phelps, of Pittsburgh; Henry Heatwole, a park
collaborator, who is with us today; Hugh Crandall; Charles E.
Stevens of Charlottesville, Virginia, also with us today;
and many seasonal park employees - there are several, so
unfortunately I won't cite each one by name. Their contri-
butions have been significant, particularly in documenting
more remote areas of the park, and their records have
provided valuable supplements to the check list of the park
In the 1960's, other publications about the plant life in the
park became available. Most notably, in 1965 Arthur Stupka
published his Wildf lowers in Color , a "tri-Park" book. It
is a superb publication with very good kodachrome reproductions
of the wildf lowers growing in Shenandoah National Park, the
Blue Ridge Parkway and the Great Smoky Mountains National
Park. For the first time we had a comprehensive or much larger
publication dealing with the wildf lowers , perhaps the vege-
tation most attractive to many of the park visitors.
In 1965 Fosberg and I published yet another supplement to
the park's Check List, adding to the record a more detailed
study than had yet been done of genera such as the genus
Tilia , the basswoods, a rather complex genus found growing
naturally throughout most of eastern North America. As
many as four different taxa or species had been described
for this genus in the park. However, a recent monograph
helps to explain some of the floristic problems. We now
think there's actually just one species growing in the
park area [which means I must update Trees of Shenandoah
National Park ] . The genus Crataegus , hawthorns , also has
been given some attention, but it remains a problem group
despite our best efforts.
When I joined the staff of the Shenandoah National Park I
continued my collections there. A period at the National
Arboretum in Washington engendered an interest in cultivated
plants, or plants persisting from cultivation, in areas like
the park. Many of these I had documented during the years
I worked here as a ranger-naturalist. In 1966, I published
a small paper on many of the ornamentals , both woody
and non-woody, found growing or persisting at old homesites
in the park area. One superb place to locate exotic
ornamentals is near the old Judd property at Skyland. There
are more exotics persisting there than any place else in
In 1967, I published another supplement to the "Check List"
of park plants, and in 1968, I published a book dealing with
the identification of the trees of Shenandoah National Park.
Subsequently, more species have been identified and I think
the book is ready for updating.
A further supplement to the Check List was published in 1972.
The total known number of species in the park was then just
under 1200. We have actually catalogued 1195 taxa used to
include species, sub-species, etc. for the park area. In
1972, I also published or prepared the book on ferns and the
fern allies of the park as proposed by the Natural History Assoc-
ciation. This was the first major treatment given to that
interesting group of vascular plants.
What is going to happen in the future? Hopefully botanists,
both professional and amateur, will continue to study in
the park and to document and publish their findings. I
feel strongly that one's knowledge of the flora is critical
to any other research involving the park vegetation. Mr.
Stephens is going to publish another supplement to the
Check List, setting many new records. This will be in print
in the next year or so. Dr. Fosberg, who unfortunately could
not be here today, has for some years now been trying to
correlate the original Check List and all of the supplements
into one document, annotated with habitat data. I have been
working on a supplemental list myself with assistance from
Mr. Peterson, an amateur botanist from the Washington area
who has spent hours in the park each year looking for some
rather unusual plants and trying to fully document each of
the park taxa. Individuals like Dr. Fisher are doing their
research on some of the various species found specifically
at old homesitas in the area.
There are undoubtedly other people who have been collecting,
f loristically speaking, data from the park area, many of
whom are unknown to me. But hopefully through meetings such
as this we can exchange ideas and information which increase
our awareness of the park vegetation. Some day we might have
a complete list of these plants , if indeed it is possible to
do such a project in view of the fact that there are always
some plants moving in or moving out of the area. Some botan-
ists say they like to study plants and collect plants
because they don't move around like insects. Some species
do migrate; they don't have limbs or legs, but they
certainly do migrate into and out of areas , and for this
reason the flora of the park will probably never be 100%
A SELECTED BIBLIOGRAPHY OF BOTANICAL LITERATURE
ON SHENANDOAH NATIONAL PARK, VIRGINIA
Fosberg, F.R. Notes on the Shenandoah National Park Flora.
(Fourth Supp.). Castanea 24: 135-143. 1959.
Fosberg, F.R. and E.H. Walker. A Preliminary Check List
of the Plants in the Shenandoah National Park, Virginia
Castanea 6: 89-136. 1941.
First Supplement to a Preliminary Check List of
Plants in the Shenandoah National Park, Virginia
Castanea 8: 109-115. 1943.
_. Second Supplement to a Preliminary Check List
of Plants in the Shenandoah National Park, Virginia.
Castanea 13: 83-92. 1948.
Third Supplement to a Preliminary Check List of
Plants in the Shenandoah National Park, Virginia
Castanea 20: 61-70. 1955.
Fosberg, F.R. and P.M. Mazzeo. Further Notes on Shenandoah
National Park Plants. (Fifth Supp.). Castanea 30: 191-
Mazzeo, P.M. New Additions to the Shenandoah National Park
Flora. (Sixth Supp.). Castanea 31: 236-240. 1966.
. Native and Exotic Ornamentals in the Shenandoah
National Park. Amer. Hort. Mag. 45: 419-421. 1966.
New Additions and Notes to the Shenandoah National
Park Flora. (Seventh Supp.). Castanea 32: 177-183. 1967.
_. Notes on the Conifers of the Shenandoah National
Park. Castanea 31: 240-247. 1966.
_. Trees of Shenandoah National Park in the Blue
Ridge Mountains of Virginia. 80 pp. , Illus. , Shenandoah
Natural History Association, Bull. No. 3, Luray ,
_. Further Notes on the Flora of The Shenandoah National
Park, Virginia. (Eighth Supp.). Castanea 37: 168-178.
. Ferns and Fern Allies of Shenandoah National Park.
52 pp., Illus., Shenandoah Natural History Association,
Bull. No. 6, Luray, Virginia. 1972.
Schnooberger , Irma and F.E. Wayne. The Bryophytes of
Shenandoah National Park, Virginia. Bull. Torrey
Club 72: 506-520. 1945.
Sharpe , G. and W. 101 Wildf lowers of Shenandoah National
Park. 1-40 pp., Illus., Univ. of Wash. Press, Seattle.
Stevenson, J. A. A Preliminary List of the Fungi of Shenan-
doah National Park. Claytonia 3: 21-28. 1936; 3: 31-
Stupka, A. Wildf lowers in Color. XIV plus 144 pp., Illus.,
Harper and Row, New York. 1965.
Jack W. Raybourne*
I'd like to brief you, if I may, a little bit on the work
we're conducting in Virginia on the black bear. It's an
animal that is quite controversial, to say the least. It's
an animal also that is very, very difficult to get much
good information on. Our aim in the study is to establish
biological bases on which to manage Virginia's bear
population. There are different avenues of enjoyment for
different individuals and we're going to try to come up
with some ideas that will help not only the hunting public
that I work for but also the visitor who enjoys seeing
these animals, as all of us do.
Our study of the black bear is state-wide in scope and includes
lands here on the Shenandoah National Park where we find
about 25%, roughly, of the state-wide black bear population
as we currently know it. Other prime study areas are the
United States Forest Serivce lands, Virginia Game Commission
lands and selected private lands in the Commonwealth. The
Shenandoah National Park serves as the primary control area,
if you will, for the studies that we are doing. It is the
largest single block of "non-hunted" land that we have availa-
ble in the state. It gives us a good "control" from the stand-
point that it shows us what we should expect in terms of
population phenomena: births, deaths, and movements which
should occur in a non-hunted area. We do know that this
area is illegally hunted, regardless of how we might want
to think of it. The periphery, of course, can be legally
hunted, It's a large area; manpower is limited and certain
types of individuals will take advantage of the situation.
Still, it serves as the best available control area for
We are trying to establish an age and sex structure on the
bear population similar to what a life insurance company
*Game Research Biologist, Virginia Commission of Game and
does with humans. From this we can predict, based on the
production rates , and the mortality factors (not only
hunting but accidental causes of death, disease, and what
have you) that occur in a population. Reproductive factors
are highly important in black bears since they are so
unusual in their biology. They are "induced ovulators" and
"delayed implanters." The former "fifty-cent words" meaning
they shed their ova during the physical act of mating,
as do rabbits. They are also delayed implanters like the
weasel and mink family. The fertilized ovum implants at some
later point in the gestation period. In the case of bear,
which normally breed June-August, the fertilized ovum
divided into two, then four, eight, sixteen cells to a
bias tula stage. It then free floats in the uterus until about
mid-December at which time light conditions are such that it
implants into the. wall of the uterus and begins a very rapid
development. The young are born in late January or early
February. The black bear has both of two conditions that are
very unusual in the animal kingdom. In addition they only
breed every other year and don't reach normal maturity until
three years of age.
We have two studies in progress designed to improve our
overall knowledge of this fine animal. I think about the
best way to show you what we're doing is by way of photographs,
I'll describe a bit of the work we're doing, what we
hope to accomplish and some of what we've found out to date.
We have one more year ahead of us of actual trapping, tagging-
type work. The primary thing that we're after is a small
premolar tooth with which we can establish a bear's age.
The Game Commission, National Park Service, and the U.S.
Forest Service have collaborated in this study of the black
bear. The problems associated with such an investigation,
though great, have fortunately now been overcome to a large
extent. The first problem primarily concerned terrain.
Bears live in typically remote, inaccessible, very rugged
terrain that creates problems for researchers in getting
equipment into the study area. Additionally, because of their
low production potential, bears simply do not provide as
great numbers of animals to study as do deer, turkeys,
squirrels, etc. Compounding these two problems has been a
means of handling bears in a manner safe to the operator and
the animal itself. We now have tools available to us that
will allow us to do this.
There is a Southeastern Association of Game and Fish Commis-
sioners which some of you may be familiar with. I am a
member of the Black Bear Sub-Committee under this organization
which is coordinating various research studies designed to
maximize several phases of bear research simultaneously.
We have divided the "puzzle" so that each researcher is
working on a separate "piece" of the unknown. It is planned
that this knowledge be pooled so we can put the puzzle
together as quickly as possible. Each state or set of states
has a different problem such as reproduction, home range,
habitat, determination of age and sex structures, etc.
We're trying to gain as much as we can as quickly as we can
on this animal now that we have the tools available.
Bears can do a considerable amount of damage. They are a
very powerful animal. There's nothing quite like coming back
and finding a convertible, with the top destroyed, "easy
pickings" for a bear, in which someone has left food items.
This becomes a real problem for the park and also for the
visitor who is unfortunate enough to have left something in
his Car which is attractive to a bear.
I want to point out that of the many bears we've trapped
in this park, only about 10% have been known to frequent
campgrounds at all. The other 907 o are free-roaming, free-ranging
wild black bears that stay in back country areas. Fortunately,
the Shenandoah has not had, to my knowledge, the "panhandling
bear" evident in the Great Smoky Mountain National Park.
Bears cause some crop and property damage to adjacent land
owners. This occurs primarily to corn from July to September
when corn is in the tender milk stage. The natural fruits and
berries are gone and, at this point, nuts, acorns, etc.
have not yet fallen. Fresh corn is attractive, to say the
least. It wouldn't be so bad if the bears' activities were
confined to eating, but they destroy a lot while fighting,
wrestling, etc., especially the young males. We've observed
bears literally riding down a row of corn, allowing those big
stalks to run across the chest. It evidently fells good!
We caught fourteen bears in one farmer's corn field in a
week's time. They can destroy a tenth of an acre in one
night. If a farmer has a corn patch in a small open field
that's rocky, mediocre farm land to begin with, it's all
he's got; and if it's right next to "Bear Heaven," he's
got a problem! Fortunately we've been able to take care of
many of these landowner complaints. We trap and relocate
problem animals to a new habitat in western areas of the
state with the hope of "rehabilitating" them. A percentage of
them do return.
Black bears are such creatures of habit that instead of
making evenly-depressed trails they form little pads or
depressions that are rather obvious in heavily-used bear
country. Where you don't have deer in the area you can see
this fairly readily. Each bear travelling the trail steps
in the footprints of its predecessor until obvious depressions
result. This habit is a "natural" for using a new type of
trap known as the Aldrich Foot Snare. Previously, when
anyone mentioned bear traps the listener thought of powerful
steel traps that were extrememly dangerous. The Aldrich
Foot Snare is a very safe, humane trap. A small child can
step into one of these and get out of it just by simply
loosening the noose. It will hold the animal in place until
we get there with a dart gun. We simply dig up one of the
depressions on a bear trail and set the snare noose, made
of 42 inch aircraft cable with 4,200 pounds of tensile
strength. We also can use baited sets with this type trap.
The simplest baited set consists of two small anchor trees,
four to six inches in diameter, about two feet apart. Then
we build a closed "horseshoe" out of small saplings about
four feet deep, with the two small trees serving as the mouth
of the horseshoe. The set is then baited. They'll come around
the open end. Black bears have very soft, sensitive pads
on the bottoms of their feet. They won't step on anything
sharp, such as a stone or a stick, that they can avoid. By
strategically placing stepping stones and sticks, we can
direct his feet into the area of the snare trigger.
The culvert trap is used exclusively in the Shenandoah
National Park since there is less danger to the public
when the bear is in this type of trap. They are marked
very clearly so that anyone knows that it is a bear trap.
The culvert trap is potentially more dangerous to people
than the snare, particularly if small children were to be
playing around it. The door weighs about 50 pounds. We visit
these traps daily. They weigh approximately 500 pounds
empty. With a device that heavy, plus a bear that may weigh
as much, handling of traps was formerly a problem. To solve
this we strengthened the truck's tail gate, attached a cargo
roller track, and added an electric boat winch. The winch
has been absolutely indispensable to us. We use it for all
loading of traps and weighing of animals.
The new drug which we have available to us now is known
as M-99 Etorphine. It's a synthetic morphine compound and is
extremely powerful and has an antagonist that works with it.
It generally takes effect in 15 minutes, making the animal
"high as a kite." The animal's respiration rate drops
dramatically, but the heart rate remains esentially stable,
about one beat per second. We don't attempt to handle the
animals now until the respiration rate drops to about
one inspiration per twenty seconds. Normally they pant very
quickly, like a dog.
There are two different kinds of injecting devices, one
for liquids and one for solids. The drugs currently in
use come in liquid form. The drug formerly used was known
as Sucostrin (Succinylcholine Chloride) . It is a skeletal
muscle immobilizer which was pre-assembled in disposable darts
with excellent shelf-life in the dry form. It can be kept
almost indefinitely, pre-loaded. Unfortunately, in the case
of an accidental human injection or bear overdose there is
no antagonist for Sucostrin except oxygen. With the dosage
required to immobilize a black bear, accidental injection
would probably mean certain death for a human.
To my knowledge, the drug that we are now using has not
been tested on humans. Injection is done at point blank
range with a CO2 dart pistol. Within 15 minutes, normally,
the bear is sufficiently anesthetized to handle. The first
thing we do is to weigh each animal and affix a numbered metal
tag in each ear. Each tag has a reward inscription to en-
courage individuals to report any dead bears to our agency.
This gives us an opportunity to monitor bear mortality
and survival on a sample basis by sex, age, time of year,
etc. Tag data also provides information on weight gain and
We collect a variety of measurements on these animals once
we've got them in hand. Some information collected is not
needed presently, but is collected with the possiblity of
future use. Various head measurements are taken along with
total body length, shoulder height, heart girth and measure-
ment of the front and rear pads. There appears to be a degree
of correlation between heart girth and weight by sex.
Gerald Blank is a trapping specialist with our agency.
He's been instrumental in developing a lot of the techniques
that we utilize not only on black bears but for live trapping
other species as well.
We take an extra step to permanently identify individual
bears in addition to ear tagging. Some studies in other
states have indicated that one or both ear tags may be lost
the first year, particularly by the males, due to fighting,
greater movement, etc. We tattoo the lowest ear tag number
inside the upper lip as a permanent means of identification
The primary thing that we're after is an age and sex structure
on the population. Establishing an accurate age has been the
biggest problem that has beset black bear researchers. Turkey,
deer, and many other species can be aged very accurately.
Age and sex data along with reproduction data has allowed
us to manage deer populations to numbers far greater than
the Pilgrims found when they came to this country. Current
statewide deer harvests exceed 66,000 animals due largely
to planned management on a sustained-yield basis. We've not
been able to do this with black bear because of past diffi-
culties in aging. We formerly could call a bear a cub,
possibly a yearling or an adult. "An adult" is a broad
category. Age of adults is important because of its bearing
on reproduction, particularly in the case of the female.
Therefore, we need to have an age and sex structure.
There is a new technique that now enables us to get within
one year of a black bear's age. The technique involves
examination of cross-sections of tooth samples. We pull
a small premolar, just alongside the large canine in the
upper jaw, from animals that we trap. Additionally, the
hunters in the state who are successful in harvesting a
black bear return to us voluntarily a front portion of
the lower jaw from which we extract the large canines and
do a cross-section on that to see the cementum annul i that
lie within. The principle is almost exactly the same as in-
volved in tree growth. During the spring and summer, when
vegetation is lush and nutrition is at its highest, there
is active depositing of bone and tooth cells. This depositing
slacks off during the winter months, resulting in alternate
layers annul i which can be observed and counted under
the microscope. The first upper premolars lie immediately
behind the large canines. Dental forceps were used for
initial premolar extractions, but were discontinued in favor
of a standard 8-inch screwdriver. Professionally, this may
sound crude, but it's the best tool we've found yet. The
matchhead size tooth lies immediately adjacent to the large
canine. By inserting the blade of the screwdriver between
the two and twisting, the tiny tooth will roll out of its
socket with little resulting gum damage. Removal of an
upper premolar provides good drainage and we have found
that an oral antiseptic is not necessary.
This photograph of an unprocessed canine tooth cross-section
(see Figure 1, page 34) will give you a rough idea of what
we are looking for. This is just a very rough cross -section ,
polished just a little bit. The area on the extreme left, the
white band, is the enamel portion of the tooth. The next layer
containing the cementum layers that we're after. The inner-
most region is the root canal, which closes in with age.
The tooth samples are put in a formic acid solution for
about a week. This de-calcifies or removes all the enamel
on the tooth leaving it soft and pliable, almost rubbery.
It is then placed in a paraffin bed and a freezing microtome
is used to section it to about 5 microns which is then
mounted on a slide to go through a stain, alcohol and
washing procedure. You end up with something like this (see
Figure 2, page 34). This particular photograph is not a photo-
micrograph, but does show the presence of the annul i . The enamel
has been removed by the acid. The area on the extreme left
FIGURE 1. Unprocessed canine tooth cross-section
FIGURE 2. Processed canine tooth cross-section, annular
rings visible on the extreme left hand margin
hand margin of this photograph of the tooth section is the
dentine. Within it you can see the annul i . On this photograph
you can count most, but not all of the annul i which tend to
be compacted in older animals. Under the microscope the
annul i can be separated. This particular animal was a 19-3/4
year-old male that was killed in Rockbridge County in 1973.
It was killed on the Game Commission's Goshen-Little North
Mountain Wildlife Management Area. The oldest specimen
we've had, a 20-3/4 year-old female, was also obtained from
one of our hunting areas. She had been tagged originally on
the Big Levels area of Augusta County in 1958 and was esti-
mated to be 2-1/2 years-old when captured. Interestingly,
she was killed within 1/4 mile of the original trapsite.
The oldest animal that we have trapped to date was a 16-3/4
year-old male weighing 360 lbs. trapped here in the park in
1975. It was not the largest animal trapped. Weights of bears
handled have varied from 8 pounds to a known 580. We've
had two males exceed our earlier 600-lb. scale capacity. Drug
dosages indicated weights for these two animals of 705 lbs.
and 750 lbs. for the 7-1/4 year-old and 10-1/4 year-old
bears respectively. We have since acquired a friction
tensiometer with capabilities of + 1% accuracy up to 1,000
lbs. Unfortunately, we've not been able to recapture either of
those two animals to document their true weights.
Following processing, the antagonist for the original drug
(M50-50 Diprenorphine) is injected directly into the femoral
artery. The animals are normally "up and running" within
1-3 minutes. Subcutaneous or intra-muscular injections may
require 20-45 minutes for recovery. We have a number of
visitors along occasionally. The recovery phase is always
a bit dramatic for them. We have a standard "three-minute
rule" now. If the bear hasn't recovered within three minutes,
our guest gets to walk up to the bear and shake him with his
One of the first signs of initial recovery is the rapid return
of the respiration rate to normal "panting." This is followed
by twitching movements of the ears while the animal lies
quietly. Once this stage is reached, any sudden noise
will generally bring them up at a run. We have yet to have
the first agressive response following recovery from any of
the nearly 500 animals handled. Their natural reaction is
to instinctively retreat to the nearest cover available.
I'd like to introduce some of the data we've compiled thus
far. For bears trapped and harvested from 1972 to 1974, the
average age for the harvest sample was 4.2 years for males,
5.83 years for females and 4.83 years for combined sexes.
The harvest sample doesn't differ greatly from the trapping
sample. The average age for the trapping sample was 3.54
years for males, 6.19 years for females and 4.62 years for
combined sexes. Female survival appears greater in both
samples, especially the trapping sample.
A comparison of age and sex structures of both samples
indicates certain similarities . Both harvest and trapping
samples are composed primarily of younger age (1-3 year-old)
male bears. Females predominate in the older age classes
in both samples.
We get a striking contrast when we examine the population
structure of the bears that have been tagged and subsequently
harvested, poached or accidently killed by vehicles. No
females appear in this sample beyond 6 years of age! The
great majority of these bears were trapped in the park and
subsequently harvested in close association with the park.
The data imply that the female segment of the population
receives a large degree of protection by virtue of the size
and security of preserved lands. Females appear to be "home
bodies," occupying a relatively small home range of 1-10
square miles; whereas males may use from 10-100 square miles.
The greater range of the male frequently carries him away
from the protection of the park to areas where he may be
We examined the proportion of the tagged bears harvested
annually as a means of estimating the proportion of the total
population harvested annually. We have tagged 231 bears from
1972 to 1975. Eighty-four (84) tagged bears are known to
have been removed from the population to date . (36 . 47,) .
Fifty-six (56) of the 231 tagged bears were recovered the
first fall following tagging (avg. 247,). Mortality figures
are minimum known reported kills. Unreported illegal hunting
no doubt has removed additional tagged animals from the
In four years , 9 of the 12 animals trapped and tagged in
1972 are gone from the population (75%). In 1973, we trapped
and tagged 97 bears in the Shenandoah National Park. Thirty-
two and nine tenths percent (32.97o) were harvested the first
year. Not all this was legal. In 1974, an additional 97>
were removed. An additional 57, was removed in 19 75. The
total to date removed from the population in a three-year
period is almost 507,. Average mortality for the three
trapping periods provide at least two years recovery data
indicating that 43.97, of the tagged population is gone within
a two-year period. Since the majority of the tagged bear
mortality is closely associated with the park, the observed
mortality should be considered a minimum when applied to
hunting lands .
We have added tremendously to our knowledge of the black
bear in a very short time. In addition to age and sex struc-
ture data, we are obtaining new knowledge on the handling
of nuisance bears, movements, home ranges, reproduction
and mortality. We wish to extend our thanks to the personnel
of the Shenandoah National Park for their kind assistance
and for allowing us to use this area for intensive study of
this fine animal.
STATUS OF KNOWLEDGE OF THE GEOLOGY
OF SHENANDOAH NATIONAL PARK
John C . Reed, Jr .*
I will talk a little about the status of our knowledge of the
geology in the park and surrounding regions, but perhaps it
is appropriate to start with a couple of remarks about
research in the national parks in general. It seems to me
that there are three general types of research that go on in
the parks .
The first type is research which is directly related in some
way to the management, regulation, development or interpre-
tation of a park. For example, the studies of the burns on
Big Meadows have a bearing on management. Studies of the
geology related to the location of ground water resources
for camp-grounds have a bearing on development .
A second kind undertaken here because the park provides a
controlled setting necessary for that particular type of
research, would generally be biological research of one kind
or another where you need a protected population or a protected
The third type of research is undertaken not because it's
a park area, but because the park is just part of the general
area of study. Most geologic studies fall in the latter
category. Obviously, studies of geology do play a part in the
interpretive program in a park and in a few cases play a part
in the management and development plans . But by and large
in geology we make the studies because the park is part of
the broader area of interest.
So let's now take a look at where Shenandoah fits into the
geology of this part of the country. There are obvious
differences in the landscape and physiography of the different
*Chief, Office of Environmental Geology, U.S. Geological
parts of this region: the Blue Ridge, the Great Valley, the
Valley and Ridge Province, the Appalachian Plateau to the
west, the Piedmont Plateau and the Atlantic Coastal Plain
with the great estuaries formed by drowned rivers such as
Starting with the Blue Ridge, we have a great upfold in the
core of which are exposed ancient granite gneisses . These are
flanked by a series of greenstones and sedimentary rocks
known as the Catoctin Formation which are well described in
the literature of the park. This whole unit is one great
upfold, so that the rocks on the west side continue right
around the nose to appear again on the east side.
West of the Blue Ridge are the thick sequences of folded
limestones, shales, and sandstones that underlie the Valley
and Ridge Province. The layers of sandstone resist erosion and
stand out to form ridges. The limestone and shale layers
form the valleys . These long continuous ridges and intervening
valleys are obvious on a satellite photograph of the region.
East of the Blue Ridge is the Piedmont Plateau, underlain
by a complex series of metamorphosed and highly contorted
rocks that originally were sedimentary and volcanic rocks
but which are now so highly altered and deformed that their
original character is difficult to decipher. Chiefly these
are schists and gneisses but in a few places there are
downfolds of less metamorphosed rocks, which occasionally
contain fossils . Some of these fossils are of the same age as
the fossils contained in some of the unmet amor phosed sedimen-
tary rocks west of the Blue Ridge.
East of the Piedmont Plateau is the wide expanse of the
Atlantic Coastal Plain, underlain by layers of soft sand and
clay that form a wedge that thickens seaward and actually
extends hundreds of miles offshore. It is the offshore part
of this wedge that may contain oil and gas deposits on the
Atlantic Continental Shelf.
One other unit that I neglected to point out to you before
is a series of basins just east of the Blue Ridge and in
general separating the Blue Ridge from the Piedmont. These
basins contain sedimentary rocks that are older than those
of the Coastal Plain, but much younger than those of the
Valley and Ridge, Blue Ridge, or Piedmont. These are the
red sandstones and shales that underlie the area between
Culpeper and Manassas . Locally these rocks contain tracks of
dinosaurs. The basins characteristically are bounded by faults
on one side and by an erosional contact on the other.
This gives you a rough feeling of the variety of geology
with which we deal and a general idea of where these various
rock types are found. But what I really was supposed to talk
about is the status of our knowledge of the geology. I think
perhaps the most profitable way to do this is to talk about
the advances in our knowledge over the last fifteen or twenty
The general outline of the geologic framework I have described
was well known by the 1930's. Studies had gone on in the park
area as early as 1880 and by 1930 we knew the basic outline.
But in the past forty years, there have been three major
advances in the knowledge of geology as a whole and the
eastern United States in particular.
The first of these advances is the detailed knowledge of
rock locations and arrangements gained as a result of hard
work by survey parties and mapping teams . A geologic map
of Virginia was published in 1958. Since the publication
of that map, detailed geologic mapping has proceeded to a
point where the entire area of Shenandoah National Park
has been mapped at a scale of one inch to a mile . I under-
stand that this map will be published by the Virginia Division
of Mineral Resources by mid-summer. At the same time, geologic
mapping has been going on in a number of other areas: in the
northern part of the Blue Ridge, in the area between Quantico
and Fredericksburg, in the Richmond area, and elsewhere in
the Blue Ridge, Piedmont, and Valley and Ridge. These studies
have been under the auspices of the Virginia Division of
Mineral Resources, the U.S. Geological Survey, and a number
of colleges and universities .
In conjunction with the geologic mapping we have begun to
learn a great deal more about the origin of various rock
types and about the relations of one group of rocks to another.
For example, during the early mapping the origin of the
greenstone here in the Blue Ridge was not understood. Since
that time, it has been well established that the greenstones
were lavas . We can now talk about what kind of lavas they
were and under what sort of conditions they were erupted.
Similarly, sizable bodies of rocks in the Piedmont that were
previously thought to have been of igneous origin--granites
of some kind or another--have now been proven to be deposits
formed by vast chaotic submarine slides, subsequently meta-
morphosed and uplifted, and now in a state that is difficult
to distinguish from igneous rocks. Once we understand the
origin of such rocks we can better comprehend the geologic
history of the region.
One of the most difficult problems the early geologists
faced was trying to discover the relationship between the
sedimentary rocks west of the Blue Ridge and the metamorphosed
rocks east of the Blue Ridge--in other words, the relationship
between the rocks of the Valley and Ridge Province and the
rocks of the Piedmont Province. The reason this has been so
difficult to establish is that throughout most of this part
of the Appalachian Mountains, the Triassic basins separate
the Blue Ridge and the Piedmont, and there is no way to trace
one group of rocks into another. But within the last decade,
the relations have become pretty well established by detailed
studies of the arrangement of the rocks and the structures
that they contain. Careful field studies of this kind represent
one of the major fronts on which geologic knowledge has
Another major advance in our knowledge, one that is equally
important, has been the development of ways of determining
the absolute ages of rocks and minerals. Up until about 1950,
geologists could generally determine that one rock body was
older or younger than another nearby body. We could determine
that one rock stratum containing fossils was older, younger,
or equivalent in age to another fossilif erous rock stratum
in some other part of the world by studying the fossils, but
we had no way of establishing the absolute age of the rocks.
The techniques of geochronology , or determining absolute
ages using the decay rates of natural radioactive isotopes,
have become some of the most powerful geologic tools that
have evolved in the last few decades.
Let me describe some of the results of these dating studies.
The accepted figure for the age of the earth is now in the
neighborhood of 4.5 billion years. This, incidentally, is
about the age of the oldest rocks returned from the moon.
If we take a standard yardstick and let it represent the age
of the earth, a billion years is equivalent to about eight
inches. The major geologic eras are the Paleozoic, the Meso-
zoic, and the Cenozoic. The first well organized fossils on
which our fossil time scale depends appears about 550 million
years ago. Thus most of the rocks that we are able to date
up until the advent of geochronology occupied only the last
5 inches of the yardstick of geologic time. The time since
the origin of man represents only about the last l/50th of
an inch of that yardstick!
In order to illustrate the vastness of geologic time that
modern geochronology has established, let me ask you to imagine
walking backwards in time at the rate of about one step a year.
It would take you about 115 steps, or slightly less than the
length of a football field, to get back to the time of the
Civil War. One and a third football fields would take you to
the time of the Revolution; and you'd have walked a quarter
of a mile to get back to the time of Columbus. You'd have
walked somewhat less than five miles to get back to the
building of the Pyramids of Egypt and about 1000 miles to
get back to the time of the first man. To get back to the
beginning of the Mesozoic Era, the age of the dinosaurs,
you'd have walked 65,000 miles, or 2% times around the world.
In order to get back to the age of the earth, you'd have walked
4% times the distance to the moon.
When we consider the geology of Shenandoah, we find that the
granites and gneisses that make up the core of the Blue
Ridge range in age from about 1 billion years to about 1.1
billion years . The lavas of the Catoctin Formation now are
thought to have an age of about 820 million years . This age
is not precisely determined but it's the best information we
have at the moment. As we go south in the Blue Ridge, we find
vast thicknesses of rocks of approximately similar age. The
Great Smoky Mountains are underlain by tens of thousands of
feet of sedimentary rock the age of which is believed to
be about equivalent to the age of the Catoctin lavas here .
The next younger group of rocks exposed in the park are the
basal beds of the sequence of sedimentary rocks of the Valley
and Ridge Province. These are the quartzites and shales of the
Chilhowee Group, that are found in a few places on the crest
of the Blue Ridge, but which crop out almost continuously
along the west foot of the Blue Ridge. They have an age of
just a little bit more than half a billion years, about 550
million years .
The younger sedimentary rocks of the Valley and Ridge Province
form a continuous sequence that goes upward in age to about
250 million years .
Rocks in the Triassic basins east of the Blue Ridge range in
age from about 180 to 190 million years, and the strata of
the Atlantic Coastal Plain have an age of about 80 million
years going up almost to the present.
Lastly, we find the youngest deposits in the Blue Ridge-- the
talus slopes in which the salamanders live, and the other
Even more impressive than the length of time that is repre-
sented by these rocks is the fact that all rocks preserved in
this part of the Blue Ridge represent only about 10 percent
of the time that has elapsed since formation of the earth.
We must also be aware of the episodes during which the rocks
were folded, faulted, and metamorphosed to form the Appalachian
Mountains. These episodes climaxed about 450, 350, and 230
million years ago. This understanding of the framework of
geologic time is the second main front on which the knowledge
of geology has advanced in the last decade or two.
The third advance has been the development within the last
fifteen years of the concept of plate tectonics. This has
had an effect on the earth sciences that is just as funda-
mental and just as far reaching as the development of the
theory of evolution was for the biological sciences .
Until the development of the plate tectonic concept, we were
pretty much observing isolated facts and describing isolated
phenomena without any sort of integrating model. Briefly, the
idea is that the entire crust of the earth is divided into a
small number of relatively rigid plates that are slowly
moving with respect to one another. The plates are moving
away from each other at the mid-ocean ridges such as the Mid-
Atlantic Ridge and the East Pacific Rise, while the plates
are converging at the ocean trenches .
Consider a mid-ocean ridge with crust moving away from it
on both sides and new crust forming in the middle. The pro-
cess is rather like two ice floes moving apart and new ice
forming in the open water between. New crust constantly
forms in the area of volcanic activity at the crest of the
ridge, and becomes part of the plates moving away from the
ridge. What happens when one of these plates meets a plate
moving away from another ridge? What happens is that one
of the plates moves down beneath the other one. The down-
going plate is carried to a depth within the earth's mantle
where the temperatures are high enough that the plate is
melted and returned back into the mantle.
One of the rules of plate tectonics seems to be that the crust
under the oceans is thinner and denser than the crust under
the continents . When an oceanic plate meets a continental
plate, it is the oceanic plate that turns down and is con-
sumed. This process is described as subduction. Just to
give you some of the evidence on which the theory of plate
tectonics is based, we can review a world map showing the
distribution of earthquake epicenters during a ten year period
The ocean ridges are marked by a very distinct line of
earthquake epicenters, but most of the major earthquakes
occur along the subduction zones where plates are turning
down and being consumed. The pattern fits beautifully the
pattern of the plate boundaries .
Again you ask, what does this have to do with the geology of
Shenandoah? Well, I should digress just a minute and discuss
a little bit more of the detail of what is thought to happen
at one of these converging plate junctions . The oceanic plate
is colliding with the edge of a continental plate and is
going down. The continental material is presumably very
much like that exposed in the granites and gneisses here in
the Blue Ridge. As the plate goes down, the temperature
rises because of friction and some of the material at the edge
of the continental plate and some of it in the down-going
plate, is melted, moves upward, and erupts as of volcanoes.
This forms a chain of volcanic islands, much like the Island
of Japan. Earthquakes are occuring along the down-going plate
and the chain of volcanoes is forming on the overriding plate
above it. The rocks between are increasingly deformed and
belts of folds created. This goes on until another continental
plate is carried into the subduction zone. Because the continen-
tal material is lighter and thicker, it can't be subducted
and when that collision occurs the subduction stops and a
mountain chain is formed, with folded and faulted volcanic
and sedimentary strata.
With the development of the plate tectonic concept, it became
possible to begin understanding some of the fundemental
causes for the formation of the Appalachian Mountains . A
map showing a reassembly of the continents as they were thought
to have appeared about 180 million years ago would indicate
the outer edges of mountain systems which are the same age
and the same structural style as the Appalachian system.
Mountains similar to the Appalachians in Africa, in Newfound-
land, in Ireland, Great Britain, Norway and Greenland can all
be fitted into a coherent picture in which the structures and
the various rock belts can be reassembled. This mountain
system, which has been referred to as the Caledonide or
Appalachian-Caledonide system, is thought to have originated
from a collision between the African and European plates on
the east, and the American plate on the west. This collision
occured during the interval from about 450 million years ago
to about 250 million years ago.
At that time, the continents would have been assembled and
since that time they have been spreading from the Mid-Atlantic
Ridge, forming new crust until we have a situation today
wherein the old mountain system fragmented- -some parts (the
Appalachians) in North America, other parts in Africa, Green-
land, the British Isles, and Norway.
This is a very nice model of the evolution of the Appalachian
Mountain system and the Atlantic Ocean starting from about 180
million years ago and going forward. But the model can also
be applied going backward. The granites and gneisses that
form the core of the Blue Ridge, the billion year old rocks,
are presumably part of an original crustal plate that included
all of North America, Europe, and Africa. This plate was
ruptured about 800 million years ago and during that rupturing
the lavas of the Catoctin Formation welled up in the rifts
that were formed as the plate came apart. As spreading
continued the first Atlantic Ocean was formed. Many of the
sedimentary rocks which we now see in the Valley and Ridge
Province were deposited on the submerged edge of the North
American continent as that early Atlantic opened. They were
deposited on the trailing edge of the continental plate.
About 450 million years ago, for some reason, this movement
reversed and the ancestral Atlantic began to close by sub-
ducting crust along the eastern edge of the American plate.
During that interval, a chain of volcanic islands formed.
Associated sedimentary and volcanic rocks were deposited in
shallow seas behind the island chain in a setting much like
the present Sea of Japan. Finally, as subduction continued,
Africa approached North America and collided with it. The
rocks of the island arc were crumpled and metamorphosed and
these are what we now see as the metamorphosed sedimentary
and volcanic rocks of the Piedmont.
About 180 million years ago the direction of motion changed
again. The fissure between the two continents began to open
once more. As this happened, lavas which were very similar to
the old Catoctin lavas were erupted. As the continents were
pulled apart, a series of basins formed that collected debris
and alluvial materials that now form the sedimentary rocks
in the Triassic basins. As the new Atlantic continued to
open, flat-lying sedimentary layers were deposited on the
submerged trailing edge of the continent. These rocks are
the strata we now see in the Atlantic Coastal Plain. As you
see, we have now evolved from a series of isolated observa-
tions of where rocks are and how they relate to one another
to a picture that begins to make sense on a global scale,
both in space and in time. Nobody can say that all details of
this interpretation are right, but it gives us an integrating
model which can guide our observations and against which we
can check some of our conclusions .
So the three main advances in our knowledge of the geology of
Shenandoah are: greater knowledge of the regional geology,
better understanding of geologic time, and a better inte-
grating model with which to compare our observations .
In closing, it might be worth suggesting some of the lines
of geologic research that would be valuable in the future .
First of all, I think more detailed studies of the origin and
age of the granitic basement rocks is needed. This would give
us a clue to the processes and the time of formation of the
original continental plate. Also needed is further investiga-
tion of the Catoctin lavas: determining their age more
exactly, locating the centers from which they were erupted,
and learning more about the conditions under which eruptions
occurred. Further studies of the sandstones and shales of
Chilhowee Group would give us better clues to the direction
from which the materials came, the rate at which they deposited,
and the processes that affected them. Another useful group
of projects would be studies of details of the deformation
and of the metamorphic history of all of the rocks . These
studies would give us more insight into exactly what happens
during the collision of two continental plates--exactly
when the folds and faults formed, and when rocks were meta-
And last, and I think perhaps to me the most promising and
the most exciting research would be studies of the processes
by which the landscape is being shaped today--the origin of
the talus slopes, the origin of the boulder trains, the rela-
tionship between the biologic community and the geologic
setting so beautifully illustrated by the discussion of the
salamanders in another paper. It should be possible to learn
whether those talus slopes are forming today, whether they're
moving or stable. All of these are things which should be
investigated and I'm sure can be.
Studies of the details of the late Quaternary history of the
Appalachians will give us insight into the reasons for the
present distribution of the plant and animal species . These
studies are at the interface between geology, which goes
back billions of years, and archeology and history, that go
back thousands or hundreds of years .
MONITORING FOREST INSECT OUTBREAKS
IN THE SHENANDOAH
Timothy C. Tigner*
The gypsy moth is expected eventually to become a serious
pest in Virginia. This insect has aroused great public
concern in the Northeast, primarily as a severe nuisance in
residential and recreation areas. Since prolonged and exten-
sive defoliation has usually occurred on poor sites where
trees are of low commercial value, timber production has not
been significantly affected.
No one knows what impact the gypsy moth will have in Virginia.
In order to evaluate the effects of such hardwood defoliators ,
the Virginia Division of Forestry has established long-term
survey plots in areas of suitable forest type where outbreaks
are likely to occur. With cooperation from personnel of the
Shenandoah National Park, one series of plots was located
across Skyline Drive from below Stony Man summit, near Sky-
land, to a point above Whiteoak Canyon Falls. Trees in these
plots are examined periodically to assess their condition and
to monitor changes. Insect populations are evaluated at the
same time. By determining forest and insect conditions in
this area prior to gypsy moth establishment, we will be
able to evaluate the effects of future infestations more
When survey plots were established in the park during 1974,
12 percent of the study trees were dead or declining in
vigor. This reflects the poor site and generally overmature
condition of the forest. The same year, an insect called the
fall cankerworm caused heavy defoliation of about 300 acres
around Skyland. Feeding was less severe in 1975 and is not
expected to be noticeable in 1976. Any effects of this de-
foliation should show up within the next few years. Eventually,
the survey plots can be used to evaluate insect sampling
' c Entomologist , Insect & Disease Investigation, Virginia
Division of Forestry
techniques, population prediction systems, biological control
efforts, or selected aspects of environmental impact.
Hardwood defoliating insects seldom cause enough timber loss
to justify expensive control efforts; but large areas of
defoliation and large numbers of caterpillars do cause
considerable public concern for other forest values , and in
residential or recreation areas these insects can have
serious economic impact. This makes the Shenandoah National
Park particularly suitable for long-term evaluation of forest
insect conditions. Study plots are likely to remain undis-
turbed for long periods, and data collection can be modified
when necessary to supply information concerning immediate
QUESTION : Can you tell us a little bit about Dendroctonus ?
Well, the southern pine beetle has been in outbreak propor-
tions for a number of years throughout the southeast and is
truly an economic pest. It is moving north and can be found
not far from here. It's a killer. When it gets into a pine
tree the tree almost always dies. It has affected hundreds
of acres of valuable forest already. But from my standpoint,
if forest insects get into the park, their primary importance
is educational. The trees that are here in the park, including
hardwoods, are in large part valueless from a commercial
standpoint. They are overmature, they are growing on poor
sites, and commercial interest in park lands is minimal.
There will be pine trees dying; some are dying now in the
National Forest south of here. These are largely poorly-
formed trees in out-of-the-way places that couldn't be cut
if we wanted to. The way market conditions are now, we
couldn't sell them if we cut them. My own opinion is that the
sensible thing to do with infestations in the park is to
study them and try to learn something. We really know very
little about most forest insect problems because we have been
overwhelmed by their complexity.
QUESTION : How many local species of parasites are there
that might be expected to parasitize the gypsy moth?
None that we can be sure about.
QUESTION : Are there any proposals to bring parasites in?
Yes . That has been a big move by a number of agencies
including the Virginia Division of Forestry. The problem is
that we know so little about the organisms involved. We
don't know much about the gypsy moth; we don't know much
about the parasites, except which ones they are. A great
number have been introduced into this country and a number
have become established. But there is not a satisfactory
system yet for sampling the gypsy moth. And the only way
to evaluate the effect of a parasite is to see what effect
it has on the host, in this case the gypsy moth. To know
that a parasite causes 98% parasitism of a given stage is
meaningless. It doesn't mean anything at all unless you know
what that 98% parasitism does to the host population. Since
we cannot yet sample the gypsy moth very well, we don't
know the value of any of the parasites.
QUESTION : Are these parasites species specific?
There is a tremendous range. Some of them are monophagous ,
or host specific. Some of them are terribly polyphagous.
One which is established in Virginia - a parasite introduced
from Europe - has over 200 known native hosts. We haven't
recovered any other introduced species in Virginia. There
is no way of evaluating them if we did. Obviously, we cannot
establish a parasite unless it attacks insects other than
gypsy moths, because we don't have the gypsy moth yet. We
have to introduce parasites that can survive on something
else. That is not an easy thing to do, and often you never
know whether you have done it or not.